Figure 4 shows the water absorption values of the soil-cement bricks incorporated with water treatment plant
waste and cured for 28 days. It is observed that the water absorption values of the soil-cement bricks are strongly
influenced by the waste addition. In general, the water absorption has been increased with the waste addition. This
behavior can be attributed to the fact that the water treatment plant waste sample presents high percentage of clay
fraction (35 %) and high plasticity (plastic index = 25.4%), which influence the cement hydration reactions. The
water treatment plant waste absorbs large amount of water, and therefore do not have sufficient water to complete
the formation of hydrated phases of the cement. Despite this, the values of water absorption of the soil-cement
bricks incorporated with up to 1.25 % of water treatment plant waste are within the specified values (d 20 %) in
NBR 10834 (ABNT, 1994b)